Spatial navigation requires active sensory and motor processes. Animals must extract meaning from the sensory information they amass through their receptors as they search and locomote. A fundamental question in studies of sensory perception is how the blur of sensory input is converted by the nervous system into a stable perception. The proposed studies aim to elucidate the algorithm used by animals to extract a stable image of the world from input with actively mobile sensors. The experimental program addresses the question of active sensation in the context of tactile localization of objects accomplished by the exploratory whisking movements of vibrissae in the rat. The experiments involve trained animals and recording and stimulation techniques with implanted electrodes. The proposal has two major foci: First, what are the neurological reference signals in vibrissa sensory and motor cortex for whisker position? What parameters of whisking are controlled at this level? The second focus is on the sensorimotor loop linking sensory and motor vibrissa cortices. How does a fast spike train signal in sensory cortex get transformed into a slow motor control signal in motor cortex?